The Vita has a really good D-pad, Vita fighting games are really good
Blazblue CS Extend was pretty cheap when i bought it in the ps store, the story mode is basically a visual novel, and even if you don't like visual novels, there's the fighting game part of it, it is quite depp and takes a lot of time to learn, but if you do learn how to play properly, it is pretty satisfying
Guilty Gear XX Accent Core + is basically Blazblue's dad, it is faster than blazblue,
and has a more rocking soundtrack, some people(mostly long time Guilty Gear players) say Guilty Gear is better than Blazblue, but both are very enjoyable and deep, although GG is harder to learn since it doesn't come with a tutorial, at least not the psp version, but you can find tutorials online
There are 2 versions of GG on the Vita,Accent Core +, and Accent Core +R, +R is the rebalanced Vita version, but it has a smaller screen, and while i have never used it, i hear the Psp version(Accent Core+) allows you to play online, while the Vita version(+R) doesn't
Personally, i recommend the psp version, since it is the version i have played for some time, it also has a bigger screen(no,really), and if you have a psp, you can also play it there
And finally, Castlevania the Dracula X Chronicles
It is basically a remake of Castlevania Rondo of Blood, but you can unlock Castlevania Sotn, and the original Rondo of Blood, this version of Sotn comes with a few extras, such as a playable Maria